Mode of driving and straining saws



UNITED STATES PATENT OFFICE.

JAMES FISHWICK AND JOHN FISHVICK, OF LEXINGTON, KENTUCKY.

MODE OF DRIVING AND STRAINING SAWS,

Speccaton of Letters Patent No. 11,365, dated July 25, 1854:.v

To alliwhom t may concern Be it known that we, JAMES FrsHwioK and JOHNFisi-iwioir, of the city of Lexington, county of Fayette, and State ofKentucky, have `invented a new and useful lmprovement in the Applicationof Steam for the Purpose of Driving 'Saws and Keeping Them Sti-aimed;and we do hereby declare that the following is a full, clear, and exactdescription of the same, reference being had to the accompanyingdrawings, forming part of this specification, in which- Figure l, is aperspective view of a saw mill, having our invention applied. Fig-2, isa vertical section of the steam cylinders.

Similar letters of reference indicatecorresponding parts in bothfigures.

Our invention relates tothe direct driving of the saw by its attachmentdirectly to a piston working in a steam cylinder, and

. to the strainingof the same without a gate,

by the action of steam upon two above and the other below. i

lt consists inthe employment of two cylinclers andpistons of unequal.size, the lower cylinder and Qpiston being of suitable area pistons, one

to drive the saw, and `only receiving the steam during the down strokeor cut, and the upper cylinder and `piston being always full of steam,but being only just of suilicient area to keep the saw properlystrained, and to raise it., i

To enablethose skilledin the art to make and use our invention, we willproceed to describe its construction and operation.

A, is the framing of the `machine support-` ing the large lowercylinder, B, and the small upper cylinder, C, whose axes are both inline. The cylinder, B, is open at the bottom, but closed at the top`where the rod, D, of its piston, E, passes through a stufling boX,andis furnished with a-valve chest, F, like any other single actingsteam cylinder, ittedwith a slide valve, G, which opens the port, a,leading tothe top of the cylinder, and brings it in communication withthe eX- haust port, b. The valve chest is supplied with steam by a pipe,c. The upper cylinder, O, is open at `the top,but closed at the bottom,where` the rod, H, of its piston, I, passes through aistuiling boX, andit receives steam under the piston by means of a pipe, d, from the valvechest.

The saw, J, is connected to the upper piston rod by a cross head, K,working on guides, and to the lower piston rod by a cross head, L, whichalso works on guides, and which has a long straight slat at right angles`to the piston rod, to receive a sliding box, f,

in which works the crank pin,e, of a crank, M, on a shaft, N, whichcarries afly wheel, O, and an eccentric, P, to work the slide valve.

The piston, I, of the smaller cylinder, H,

being always exposed to the steam, serves the purpose of straining thesaw while the steam acts upon the larger piston, and drives down thesaw, but as soon as the steam is exhausted from the large cylinder, thesmall piston raises the saw and the large piston.

The advantages of `driving the saw, by

iconnecting it directly to the piston, `and of straining it without agate by steam acting on pistons, are well known; but these two nfeatures have never been combined so advantageously 'as in ourinvention, the principal advantages ofwhich are, that a large cylinder,full of steam, is only used to drive downthe saw, and make the cut, anda small one to raise it, thereby saving steam, and `that the same steamwhich drives the saw,

strains it.`

l/Ve do not claim the straining of saws by `steamfor other elasticfluid, neither do we keep the saw strained while cutting, and to raiseit and thelarger piston, substantially as herein described.

` JAMES FISHWIOK. JOHN FISHWICK.

Vit-nesses 1 n JN0. S. HANsBRo, D. M. BARKLEY.

